Dessicant cartridge shelf life

[Shot-N-Az]

Am I correct in assuming that installing a two year old dessicant cartridge that has been in my garage exposed to Virginia's humidity is an exercise in futility?

[SCVJeff]

The dessicant we use is dark blue when fresh (dry), and drifts toward clear as it gathers moisture

[Shot-N-Az]

Thanks guys. I'm not sure about drying the cartridge in an oven. How do you tell if it's dry?

I think I'm just going to buy a new one.

[SCVJeff]

Even if open, depending on the container you can dry them back out in the oven on low. We have even emptied the blue color changing desiccant used in air driers on isolated mountaintop sites onto foil and dry it in the sun. Takes less than 20min on a nice day.

[gdreese]

Most dessicant can be dried in the oven or microwave

[naturist]

If it was sealed in an airtight container, no. It if was indeed exposed to the humidity, then yes, totally.

[wolfe10]

In a word, YES.

And, if the filter is protecting expensive or safety equipment, short answer is get a new/fresh one.